Team not yet ready to rule out contamination from Earth either.

If you've been following the news from the Curiosity rover on Mars, you can be forgiven if you've had bad flashbacks to the Mars Phoenix lander. Back in 2008, rumors started circulating that Phoenix found evidence of life on the red planet, forcing NASA to hastily schedule a press conference in which they shot the rumors down. This time around, NASA has only itself to blame. About two weeks ago, one of its scientists told NPR the rover had made a discovery that would be "one for the history books." Naturally, he neglected to say what it was.

Speculation quickly focused on Curiosity's on-board chemistry lab, which has the ability to detect organic molecules. Although a variety of natural processes can lead to their formation, the presence of organic compounds could provide some indication of whether life was ever possible on Mars. When NASA announced a press conference on the latest Mars results, to be held at the American Geophysical Union meeting, it was careful to manage expectations. The organization noted, "Rumors of major new findings at this early stage are incorrect."

In fact, as scientist Ralf Gellert described it, the goal of the initial chemistry work was to find something completely un-special. This way, NASA could both get a picture of the average environment on the red planet and then confirm that its instruments weren't doing anything odd.

With those caveats in mind, Curiosity's instruments have seen some organic compounds, but the team running the experiment (represented by Paul Mahaffy) isn't yet ready to say that they originated on Mars. There's still a chance they represent leftover contaminants from Earth.

Ken Edgett of the Hand Lens Imager team described a bit about the sample gathering and processing. To get a sample that's typical of the surface of Mars, the team obtained some sandy material of the sort that's shifted around during the planet's epic dust storms. Curiosity took five scoops of soil at a site called Rock Nest. Edgett described the site in culinary terms: a coating of thick grains "like the salt grains on those big hot pretzels you can get" covered much finer material with grain sizes "kind of like those artificial sweeteners." After using a few scoops to clear out the chemistry system, a sample was sent through for analysis.

The new analysis, described by Mahaffy, involved heating one of the samples up to about 500°C while tracking the gas that comes off it. The most abundant gas was water, but even that had a little surprise. On Earth, one of about every 6,500 hydrogen atoms in water is a heavier isotope of hydrogen called deuterium. On Mars, the ratio of deuterium to regular hydrogen appears to be five times higher. This could be a result of Mars' gradual loss of atmospheric material, in which lighter isotopes were preferentially lost.

At higher temperatures, carbon dioxide came off the sample, and sulfur dioxide appeared at even higher temperatures. Although the soil appears to be oxidizing (more on that below), some hydrogen sulfide was present, suggesting the oxidation in the soil isn't complete.

The oxidizing material probably comes from chlorate compounds, which were also found by the Phoenix lander (in this case, they suspect calcium chlorite). A variety of chlorine compounds were detected in the gasses given off by the heated samples, probably generated as the chlorates decayed and reacted with other materials in the sample. These reactions appear to have generated a variety of methane (CH4) derivatives, with chlorine replacing a variable number of hydrogens. They've also found a four-carbon chlorinated compound in the material given off.

They aren't yet convinced that these carbon compounds aren't the result of contamination left over from the rover's time on Earth. And, if they are local, they're not sure what the chlorate compounds reacted with to produce what they see. It could potentially be something as simple as the CO2 being given off at the same time. Even if it's from the soil, there's no way of telling whether it was native to the soil or had arrived as Mars has been struck by material from comets and asteroids.

Although there were a lot of caveats, the researchers have a clear plan. Modern isotopes and chemistry can be compared to the samples they get by drilling into older rocks, and the rover carries some standardized materials to analyze for comparison. Researchers will also track how results do (or don't) change over time and as they look at different materials to get a sense of whether contamination is a problem. The Internet may want to "move at Instagram speed," as scientist John Grotzinger put it, but the team will continue to work at the cautious pace of science.

But one slide from the press conference hinted that the results were worth waiting for. To confirm that their soil sample was typical, the Curiosity team compared their results of mineral compositions to those obtained by the Spirit and Opportunity rovers. The data matched extremely well. That tells us that the hardware is working well, and should be able to analyze a variety of samples as Curiosity crawls further up Mount Sharp.

Editor's note: a reader has pointed out that our original concluding paragraph contained two significant errors. We have corrected them.

Ars Science Video >

A celebration of Cassini

A celebration of Cassini

A celebration of Cassini

Nearly 20 years ago, the Cassini-Huygens mission was launched and the spacecraft has spent the last 13 years orbiting Saturn. Cassini burned up in Saturn's atmosphere, and left an amazing legacy.

High quantities of deuterium? Could be useful. If (and I stress that is a pretty big "if") we ever figure out nuclear fusion power, deuterium is likely to be pretty key to fueling fusion reactors. It might not be worth mining Mars for them (although if we could get such cheap power, maybe), but it would certainly help establishing a Mars base. Just speculating here. The rest of the findings seem pretty mundane to me.

I find the explanation of greater frequency of heavier water on Mars interesting. I wonder if it can be explained to a lay person? I get the idea that the "heavier" water would be less likely to leave the planet, but I find it more reasonable that some kind of nuclear effect from increased solar activity reaching the surface might explain the increased frequency of heavier water.

High quantities of deuterium? Could be useful. If (and I stress that is a pretty big "if") we ever figure out nuclear fusion power, deuterium is likely to be pretty key to fueling fusion reactors. It might not be worth mining Mars for them (although if we could get such cheap power, maybe), but it would certainly help establishing a Mars base. Just speculating here. The rest of the findings seem pretty mundane to me.

I really don't think we need to go to Mars for deuterium. There's more than an ample supply on Earth. I think the estimate is that there's enough deuterium in the oceans to provide fusion fuel for about a billion years.

Furthermore, even in the medium to long term it's very unlikely we'd end up with fusion power on Mars. The fuel would be the least of our problems. You'd have to get all the other material for a reactor up there.

Thanks for this! The results are consistent with Phoenix (oxidants, specifically of perchlorate type), which is encouraging. It also goes a long way towards predicting the Vikings' results, with or without organics as source for the chlorinated organics.

As for the hype, one gets the ironic feeling that the bug-eyed monsters are the web generation. (Cue Simpsons.)

g0m3r619 wrote:

Whatever came of the discovery of formaldehyde on Mars?

There was never a confirmed discovery, but claims of observation.

I assume these claims were never confirmed, akin to how the stronger signal of methane never have been verified for certain.

iandisme wrote:

Whoever broke out the "one for the history books" line ought to be ashamed. It's hard enough to drum up good PR for NASA without some yahoo over-hyping a discovery.

It was Grotzinger. And it is correct in the sense that Curiosity will be "one for the history books". (Though I suspect he was exulting over the quality of the results, see the article. Those will be in the scientific books, and they will certainly help making Curiosity's mission a memorable one, but they won't be noticed in any lay books I'm sure.)

So he has nothing to be ashamed of (except maybe forgetting how journalists act), neither did he over-hype. The hyping journalist that was adding a qualification of "earth-shaking", now withdrawn without notice, should be ashamed. Twice.

I find the explanation of greater frequency of heavier water on Mars interesting. I wonder if it can be explained to a lay person? I get the idea that the "heavier" water would be less likely to leave the planet, but I find it more reasonable that some kind of nuclear effect from increased solar activity reaching the surface might explain the increased frequency of heavier water.

Mars' atmospere escaped through some combination of (i) insufficient gravity allowing thermal escape and (ii) the solar wind knocking high-altitude molecules with enough force to achieve escape velocy. There is debate as to whether one or the other of those causes predominated, but certainly there must be at least some element of each at play.

Both of those causes favor lighter particles escaping more easily than heavier particles. In the case of deuterium, we're really talking about water molecules escaping from the atmosphere. Water molecules with only regular hydrogen would escape the easiest. Ones with both hydrogen atoms being deuterium would be very slightly less likely to escape. Ones with one regular and one deuterium atom would fall in between. The differences would be very slight, but over the eons it took to almost completely elliminate the atmosphere, it would add up to a measurable surplus of deuterium on the planet.

I find the explanation of greater frequency of heavier water on Mars interesting. I wonder if it can be explained to a lay person? I get the idea that the "heavier" water would be less likely to leave the planet, but I find it more reasonable that some kind of nuclear effect from increased solar activity reaching the surface might explain the increased frequency of heavier water.

High quantities of deuterium? Could be useful. If (and I stress that is a pretty big "if") we ever figure out nuclear fusion power, deuterium is likely to be pretty key to fueling fusion reactors. It might not be worth mining Mars for them (although if we could get such cheap power, maybe), but it would certainly help establishing a Mars base. Just speculating here. The rest of the findings seem pretty mundane to me.

I really don't think we need to go to Mars for deuterium. There's more than an ample supply on Earth. I think the estimate is that there's enough deuterium in the oceans to provide fusion fuel for about a billion years.

Furthermore, even in the medium to long term it's very unlikely we'd end up with fusion power on Mars. The fuel would be the least of our problems. You'd have to get all the other material for a reactor up there.

Like what exactly? Do you know for a fact that the raw materials don't already exist on Mars to set up mining and manufacturing locally? You are making some baseless assumptions.

High quantities of deuterium? Could be useful. If (and I stress that is a pretty big "if") we ever figure out nuclear fusion power, deuterium is likely to be pretty key to fueling fusion reactors. It might not be worth mining Mars for them (although if we could get such cheap power, maybe), but it would certainly help establishing a Mars base. Just speculating here. The rest of the findings seem pretty mundane to me.

I really don't think we need to go to Mars for deuterium. There's more than an ample supply on Earth. I think the estimate is that there's enough deuterium in the oceans to provide fusion fuel for about a billion years.

Furthermore, even in the medium to long term it's very unlikely we'd end up with fusion power on Mars. The fuel would be the least of our problems. You'd have to get all the other material for a reactor up there.

Like what exactly? Do you know for a fact that the raw materials don't already exist on Mars to set up mining and manufacturing locally? You are making some baseless assumptions.

Are you kidding me? Mining and manufacturing in situ? In any kind of time frame that makes sense to even contemplate?

Whoever broke out the "one for the history books" line ought to be ashamed. It's hard enough to drum up good PR for NASA without some yahoo over-hyping a discovery.

It was Grotzinger. And it is correct in the sense that Curiosity will be "one for the history books". (Though I suspect he was exulting over the quality of the results, see the article. Those will be in the scientific books, and they will certainly help making Curiosity's mission a memorable one, but they won't be noticed in any lay books I'm sure.)

Then why say, "this is one for history books" months after it landed? If you're simply gonna say, "well everything they do on mars is one for the history books" then that's pretty damn lame.

What is the big deal? It would be more surprising if these and other elements are not found. The material that made up Mars ( and other bodies in space) came from a single source which would have to have all the elements that we know and maybe more than that. They may not be in equal proportions nor all of the elements may not be in the same body but they will be out there some where and will be found if searched for long enough.

That's what these NASA eggheads don't seem to get. If they say they've found something "earth shaking," the 99.9% of us that don't have a background in astrophysics are going to be sorely disappointed by anything less than some news about life, past life, or a very good potential of life.

Hey j_timmer, I think you misinterpreted the error bars. Ralf Gellert said they were there on the MER data, with no indication that there were error bars on the SAM data from Curiosity. He very clearly said that the error bars clearly represent the variation over many runs of the MER hardware, and since there is only one measurement from Curiosity, there are no error bars.

I find the explanation of greater frequency of heavier water on Mars interesting. I wonder if it can be explained to a lay person? I get the idea that the "heavier" water would be less likely to leave the planet, but I find it more reasonable that some kind of nuclear effect from increased solar activity reaching the surface might explain the increased frequency of heavier water.

Sure, it shouldn't be that hard to explain. Cosmic rays, solar radiation, and solar wind hit the upper atmosphere of mars with a certain amount of energy. That energy is imparted to particles in the atmosphere. E=mv^2, so the lighter the particle the greater the velocity, and thus the greater chance that the energy imparted will be enough to accelerate it to escape velocity from Mars. This preferential loss of lighter particles over billions of years results in significantly skewed isotope ratios.

There is no known 'nuclear effect' which would create significant amounts of deuterium as a result of solar radiation. Deuterium is created by nuclear processes inside the sun, but that deuterium would also be consumed at a faster rate than it is produced, which is why it is believed that all the deuterium we see is from gas that was never fused inside a star.

I think a straightforward application of kinetic energy is more reasonable than an unknown transmutation mechanism contra-indicated by well-working nuclear theory. Why do you disagree?

That's what these NASA eggheads don't seem to get. If they say they've found something "earth shaking," the 99.9% of us that don't have a background in astrophysics are going to be sorely disappointed by anything less than some news about life, past life, or a very good potential of life.

He didn't say that, he said "one for the history books", but sure, it sounds as if over-hyped.

John Grotzinger's mistake was forgetting that something that he says from his perspective as a scientist is going to be interpreted and paraphrased from the perspective news-hungry journalists, which is then going to be re-interpreted from the perspective of lay-people who don't much care about regular history books, much less science ones, and wouldn't find anything less than bug-eyed monsters interesting enough to write down for posterity and on that basis assume that's what he must be talking about because otherwise why would they care?

He made it clear he's aware of his mistake in the press conference.

Maybe you could do him a favor and meet him halfway, by keeping in mind that this is a scientific mission and what's scientifically historic is not what you personally would find historic.

Personally I get my Curiosity information from the MSL mission website (I'm always looking for new photos of Mars rocks with laser blast marks on them ) and responsible science journalists like Emily Lakdawalla and I was taken completely by surprise that there was apparently "hype" that these results failed to live up to.

Nothing to see here folks. The samples taken were fully exposed to the sun and other environmental conditions and have been sterilized over time. The concentrations are not significant and nothing to get your panties all in a knot about. Now, if samples were taken deep below the surface or at the bottom of a cliff protected from the elements or from within a cave...

SAM heated the samples up to ~900 C (not 500) and the preliminary thought is that the O2 is from *per*chlorate salts, not chlorates. The O2 release looks most consistent with Ca-perchlorate, not Ca-chlorite.

What is the big deal? It would be more surprising if these and other elements are not found. The material that made up Mars ( and other bodies in space) came from a single source which would have to have all the elements that we know and maybe more than that. They may not be in equal proportions nor all of the elements may not be in the same body but they will be out there some where and will be found if searched for long enough.

You are absolutely correct and I agree, but don't you think NASA is thinking the same thing you're thinking? And the big deal is that chances are there are gold on Earth there must be gold on Mars, and we the U.S. government want them. It's good on the $Dollar you know. And how about Titanium and other precious metals, and also the raw materials that we don't have here in the U.S.? We want them too.

... there must be gold on Mars, and we the U.S. government want them. It's good on the $Dollar you know. And how about Titanium and other precious metals, and also the raw materials that we don't have here in the U.S.? We want them too...

I would be curious to see your breakdown on the economy of mining precious materials on Mars. I'm sure you have it all figured out with a decent profit margin.

I know it's not going to be a cat walk setting up mining sites on Mars that I know of. It's a hard job doing anything on a weightless environment. But if there are golds found on Mars we'll figure out a economical way of getting them back here on Earth.

But like you said lets look at the profit margin first if it's profitable to do so ..

The current price of gold per ounce is around USD$1,800

$1800 x 16 oz = $28,800 per pound.

Take 1 US ton = 2,000 US pounds

$28,800 x 2,000 lbs = USD$57,600,000 ($57.6 million dollars).

I read about there is this private owned commerical space program is charging somewhere around $50 million per person for anyone who is interested in a 7 day tour around the Earth.

If this private owned space program makes money out of $50 million per person. I am sure mining gold on Mars should be profitable for the US government.

A cargo spacecraft operated by 2 to 4 crew members shipping gold back and forth from Mars shouldn't costed that much to operated when we are talking about $57.6 million per ton of gold.